B K Mueller 521-376HN Black Reducing Coupling 1.5x1.25 in

Product Description

The B K Mueller Industries 521-376HN is a black reducing coupling designed to connect pipes of two different diameters in a threaded piping system. This fitting transitions from a 1.5-inch pipe to a 1.25-inch pipe and is finished in black, indicating a malleable iron construction common in gas, air, and industrial piping applications. Sold in a package of 5 units, the 521-376HN is a standard trade fitting installed by licensed plumbers and pipefitters on commercial and residential systems where pipe size reduction is required within a threaded black iron line.

This reducing coupling is used in threaded black iron pipe systems, typically found in natural gas distribution lines, compressed air systems, and industrial fluid conveyance. The black finish is standard for gas piping applications and distinguishes the fitting from galvanized water service fittings. It is appropriate for above-ground and indoor installations where the piping system requires a concentric reduction between 1.5-inch and 1.25-inch NPT-threaded pipe segments.

Key Features

• Reduces from 1.5 inches to 1.25 inches in a single inline fitting
• Black finish standard for gas and air piping systems
• Threaded ends for connection to standard NPT black iron pipe
• Sold in a package of 5 units for job-lot convenience
• Malleable iron construction suited to moderate-pressure service

Compatibility

Designed as an OEM-style replacement or new-installation fitting for standard NPT-threaded black iron pipe systems using 1.5-inch and 1.25-inch nominal pipe sizes.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable local codes and IFGC requirements for gas piping. Shut off and depressurize the line before disassembling or adding fittings. Apply an approved thread sealant or PTFE tape rated for the service medium to all threaded connections. Do not overtighten threaded fittings, as this can crack the fitting body or distort the threads.